Study approximately 4,000 subjects previously enlisted in the Framingham Offspring Study (Cycle I) initiated in 1971. These subjects will be studied to assess cardiovascular function, cardiac structure, personal habits, and general physical condition. These studies will provide necessary information about the incidence, precursors, and etiology of "subclinical endpoints' that are becoming indicators for drug therapy and other kinds of intervention. It will also provide better identification of the "profile" for high risk of cardiovascular disease.